273 intake bolt angle

[Longgone]

I`ve been told that the bolt hole angle in a 273 intake manifold is not compatible with many of the modern LA engine aftermarket intakes. In addition the ports will not line up. What `s the deal? I`ve got a `67 273 longblock I`d like to add a 4bbl. intake on. Is there a difference in the design of the 273 heads and intake combo that prevent me from buying an aftermarket intake for say a 318? What can I use, do I have to use the factory 4bbl.? Thanks.

 

[toolmanmike]

As far as I know the 64 and 65 273's have a different angle. the rest are the same as the 318. toolmanmike

 

[Mrmopartech]

The only 273 motors with different intake bolt angles are the 64-65 273 motor,the rest use the normal intake angle,thus a person should only use a 273 or 318 intake on a 273.The 340-360 intakes are way to big of a runner and port size to put on a 273/318 and would bogg the motor and have poor fuel distribution,Mrmopartech

 

[Longgone]

Any tried and true suggestions for a 4 bbl. intake for a 67-273 ,stocker?

 

[Mrmopartech]

I would look for a old weiand or offy intake at a swap meet or see if they still make a intake for that motor from eddy and check the number,mrmopartech

 

[Longgone]

Didn`t Edelbrock make a junior version of the LD340 for the 273, 318?

 

[65Val]

Didn`t Edelbrock make a junior version of the LD340 for the 273, 318?

They sure did...The "LD4B" was the small port version of the LD340. There's one on ebay right now...

http://cgi.ebay.com/ebaymotors/Vint...020QQitemZ300015524411QQrdZ1QQsspagenameZWDVW

Now,as for intake suggestions,you could go stock Commando cast-iron intake ,casting #2536563, or #2536771 for C.A.P. ,(with the correct bolt angle and size,i might add) for your '66-'69 heads.

You could also go with a vintage Edelbrock SP2P intake ,as these have very small ports to go with your stock engine.

Hope this helps....

 

[cavemanmoron]

I am using an LD4B,
on my 318. :thumbup:

Small ports work better for street use, on a small engine.

 

[Longgone]

Thank you Toolmanmike, Mrmopartech, 65Val and Cavemanmoron, this is all good stuff! I have found and scored an LD4B w/ Eddy 500 cfm carb. I`m sure I`ll have lots more questions before they see service. Thanks

 

[65Val]

That combo should work well.Dont be tempted to over-jet the carb. Its real easy to get a stock 273 over-rich.

 

[Longgone]

This car is going to be a cruiser, so I`m going to stretch every inch of wheel roll out of every drop of fuel on this one. The other car is the one that doesn`t pass too many gas stations! LOL!